Peloursin is red French wine grape variety best known for crossing with Syrah to make the red wine grape Durif (known in the United States as Petite Sirah). The variety is believed to have originated in Isère from the northern Rhône-Alpes region. Today Peloursin can be found in some quantities in California and in the Australia wine region of Victoria.
Ampelographers believe that Peloursin originated in the Isère department near Grenoble somewhere along the Vallée du Grésivaudan. The name Peloursin likely derives from the local word pelossier used to describe the blackthorn trees that populate the area and whose fruit the Peloursin grapes have a slight resemblance to. At some point the grape was brought to the northern Franche-Comté and Savoie wine regions but it is in the Isère that the vine crossed with Syrah to produce the Durif vine.
In the 1860s, French botanist François Durif kept a nursery of several grape varieties at his home in the commune of Tullins where he most likely had plantings of both Peloursin and Syrah. At some point the two vines cross pollinated and Durif discovered a new grape variety growing in his nursery. It was identified and named Plant du Rif (later Durif) by ampelographer Victor Pulliat in 1868. Durif later made its way to California where it was eventually named Petite Sirah. In the late 20th century University of California, Davis researchers led by Dr. Carole Meredith discovered that some of the California plantings of Petite Sirah were, in fact Peloursin, and that Peloursin had a parent-offspring relationship with Durif that likely sprung from a crossing with Syrah.